Rotary movable abutment pump



My 5, 11949 J. P. JQHNSON ROTARY MOVABLE ABUTMENT PUMP Filed May 3, 1945 INVENTOR. JAMES EJO HNSON ATTORNEYS Patented July 5, 1949 UNITED STATES PATENT OFFICE ROTARY MOVABLE ABUTMENT PUMP James P. Johnson, Shaker Heights, Ohio Application May 3, 1945, Serial No. 591,684

4 Claims. 1

This invention relates as indicated to pumps and more particularly to the type of pump employing a lobed rotor and radially extending blades which engage the periphery of the rotor and divide the space about the rotor into separate pumping chambers.

In its more specific embodiments, the present invention is an improvement in the type of pump construction illustrated. for example in my copending application Serial No. 545,777, now Patent No. 2,452,468 issued October 26, 1948.

It is a principal object of this invention to pro vide a pump of the character described in which the blades are balanced so as to reduce the rate of wear in the pump while at the same time in no way interfering with the eiiicicncy of the operation of the pump.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed. out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

Fig. 1 is a section view of a complete pump of the character to which my invention relates;

Fig. 2 is a transverse section view drawn to an enlarged scale of the structure illustrated in Fig. 1 taken on a-plane substantially indicated by the line 2-2;

Figs. 3 and 4 are views similar to Fig. 2 showing, however, a slight modification in the construction of the blades; and

Fig. 5 is a fragmentary sectional view drawn to an enlarged scale of a portion of the pump as illustrated in Fig. 1.

Referring now more specifically to the drawing and more especially to Fig. 1., the pump here illustrated consists of a body or housing member generally indicated at l which is adapted to be secured as by bolts or the like to a motor such as Z by which. the pump is driven. The housing I has a closure cap or head 3 removabiy secured thereto as by bolts d. In the pump illustrated in Fig. 1 the cover 3 has three bosses each. of

which has a passage therein leading into the pump. One of such passages is an inlet or supply passage and the other two are separate outlet passages. Since the detailed construction of these features of the pump are given in my above identified copending application and since they form no part of the present invention they will not be described in greater detail at this point.

Rotatably supported in the housing l a rotor 5 in driving communication with the shaft 5 of the motor 2. The rotor 5 extends through a gland generally indicated at 1 and at its right-hand end as viewed in Fig. 1 carries a rotor head 8, the cross-sectional form of which is most clearly illustrated in Figs. 2 to 4. As illustrated, the contour of the rotor head 8 is non-circular and preferably of form such that the sum of the lengths of any two diametrically opposed radii is a constant.

The rotor head 8 is positioned in a bore 9 in the forward end of the housing 1. The bore 9 is substantially circular in its cross-section, i. e. cylindrical in form. A stator member Ill which is generally annular in form is positioned in the bore 9 and sub-divides such bore into an inner cavity i l and an outer cavity l2.

Mounted in radially extending slots in the stator member In are blades H! which at their inner ends bear against the lobed rotor 8.

The blades l3 are resiliently maintained in engagement with the rotor t by means of a solid spring annulus M which as formed may be a true circle having an inside diameter slightly less than the distance across the blades 13 so that by springing this annulus M slightly out of round it may be placed over the ends of the blades and thus resiliently urge the latter inwardly against the rotor.

As previously indicated, the blades l3 divide the pump into two pumping zones. The inlet passage H: in the body I and leading from one of the bosses in the head 3 extends byv means of branch ducts Hi to openings I! by which the fluid is supplied to the pump. The outlets for the pump are opposite the recesses l8 and are formed in the head 2.

The stator i B is provided with radially extending passages l9 adjacent each outlet port l8 and in each of such passages there is a check valve 20.

In the structure illustrated in Fig. 2, the blades l3 are chamfered at their rotor engaging ends, such chamfering facing the direction of rotation of the pump.

The operation of the pump as illustrated in Fig. 1 is briefly as follows:

Fluid is admitted through the openings H and the rotor 8 rotated in a clockwise direction as viewed in Fig. 2. Thus, a predetermined amount of fluid is trapped between the rotor and the stator and forced outwardly through the discharge openings la. The fluid in the pressure side of the pump, therefore, has an opportunity to pass outwardly through the passage !9, and build up in the outer portion l2 of the bore 9 a pressure equal to the pressure in the discharge opening 18, i. e., the same pressure which is exerted against the forward faces of the blades l3.

By having the forward edge of the blades chamfered as illustrated in Fig. 2, the blades are hydrostatically balanced, and the only pressure urging the blades inwardly toward and into engagement with the rotor is that developed by the spring annulus I4.

The construction illustrated in Fig. 4 is in every respect identical with that illustrated in Fig. 2 except that the blades I311 are chamfered on their trailing edges. When this expedient is employed then the radially outward hydrostatic pressure on the blades 13 is reduced to substantially zero, i. e. the pressure within the inlet passage 17, while the pressure within the outer portion l2 of the cavity 9 is still the same pressure as that built up in the discharge passage l8. When such expedient is employed then the resilient annulus I4 is assisted by the pressure inthe outer cavity I2 in forcing the blades into engagement with the rotor 8. II I I I I A construction which may be conveniently referred to as intermediate that 'shown in Figs. 2 and 4 is illustrated in Fig. 3 and inwh'ich the blades I3b are chamferedon both edgesthereby making the effective area of the blades subject to radially outward pressure equal to about one-half of the full cross-section of the blades.

Fromthe foregoing description, it will be observed that while only three variations have been shown, nevertheless, by changing the degree and direction of chamfe'ring a wide variety of variations in pressure between the b la des and the itor may be secured to accommodate particular conditions which may be encountered. I

A pump of this character is useful not only in pumping liquids but alsofor pumping g a s es. The pump is particularly useful pumping gases where no lubrication can be used. By making the rotor of a hard material such as tungsten carbide and the blades of hard non-metallic substance such as sapphire, the can be run for extremely long intervals without any lubrication whatsoever. I I I I Other modes'of applying the principle of the invention may be employed; change being made as regards the details described, provided the features stated any of the following claims or the equivalent of sufch be employed. I I I I, therefore, particularly point out and distinctly claim as my invention: I I I I I I 1. In a pump of the character described, the combination of a housing member having a bore therein, a substantially annular stator separating said bore into an inner portionand an outer continuous annular portion, a rotor within said stator of non-circular contourhaving a sliding fit therewith at three circumferentially and equally spaced points, such rotor contour being such that the sum of the lengths of any two diametrically opposed radii is a constant, two diametrically opposed blades reciprocably mounted in slots extending substantially radially through said stator into engagement with said rotor, said pump being provided with inlet and outlet ports leading frOm tIi'e inner portion of said bore at points respectively at epposite sides of each of said bladea pa'ssages through said stator adjacent said outlet ports and interconnecting the inner and outer portions of said bore. I I

2. In a p m of character described, the combination of a h'o'us ing member having a bore therein, a substantially annular stator separating said bore into inner and outer portions, a rotor within said stator of non-circular contour having a sliding fit therewith at three circumferentially and equally spaced points, Such rotor contour being such that the sum of the lengths of any two diametrically opposed radii is a constant, two diametrically opposed blades reciprocably mounted in slots extending substantially radially through said stator, single means resiliently urging said blades inwardly into engagement with said rotor, said pump being provided with inlet and outlet ports leading from the inher portion of said bore at points respectively at opposite sides of each of said blades, passages through said stator adjacent said outlet ports and interconnecting the inner and outer portions of said bore.

3. In a pump of the character described, the combination of a housing member having a bore therein, a substantially annular stator separating said bore into inner and outer portions, a rotor within said stator of non-circular contour having a sliding fit therewith at three circumferentially and equally spaced points, such rotor contour being such that the sum of the lengths of any two diametrically opposed radii is a constant, two diametrically opposed blades reciprocably mounted in slots extending substantially radially through said stator, a flexible annulus around said stator and in engagement with the outer ends of said blades whereby the inner ends of said blades are resiliently maintained in engagement with said rotor, said pump being provided with inlet and outlet ports leading from the inner portion of said bore at points respectively at opposite sides of each of said blades, passages through said stator adj acent said outlet ports and interconnecting the inner and outer portions of said bore.

4. In a pump of the character described, the combination of a housing member having a bore therein, a substantially annular stator Separating said bore into inner and outer portions, a rotor within said stator of non-circular contour having a sliding fit therewith at three circumferentially and equally spaced points, such rotor contour being such that the sum of the lengths of any two diametrically opposed radii is a constant, two diametrically opposed blades reciprocably mounted in slots extending substantially radially through said stator, said pump being provided with inlet and outlet ports leading from the inner portion of said bore at points respectively at opposite sides of each of said blades, passages through said stator adjacent said outlet ports and interconnecting the inner and outer portions of said bore, and a check valve in each of said passages.

JAMES P. JOHNSON.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS 

